#include<bits/stdc++.h> using namespace std; int main(){ string s; cin>>s; int i=0,j=0,k=0; while(s[i]!='@'){ if(ispunct(s[i])){ if(s[i]=='(') ++j; if(s[i]==')') ++k; }} if(j==k) cout<<"YES"; else cout<<"NO"; return 0; }